Grate and soak 2 medium russet potatoes and 1 yellow onion in salted water for 20-30 minutes to remove excess starch. Drain and squeeze out moisture.

Combine the drained potato and onion mixture with 1 beaten egg, 1/4 cup matzo meal, 1 teaspoon kosher salt, and 1/4 teaspoon ground black pepper in a mixing bowl.

Heat 1/2 inch of vegetable oil in a skillet over medium-high heat until shimmering, around 350°F.

Scoop the latke mixture into 3-inch rounds and fry for 6-10 minutes on each side until golden brown and crispy. Drain on paper towels.

Poach each large egg in gently simmering water with vinegar for 4½ to 5 minutes until the whites are set but yolks are runny.

In a blender, combine 3 egg yolks, 2 tablespoons of lemon juice, and a pinch of salt. Blend while slowly adding 1/2 cup hot melted unsalted butter until thickened.

Assemble by placing a warm latke as the base, topping with smoked salmon and a poached egg. Drizzle with hollandaise and garnish with flaky salt, pepper, and chives.